Former Indiana first lady Susan Bayh underwent brain surgery Monday for removal of a benign tumor, and her husband said her prognosis for recovery is good.

The surgery at a Washington hospital removed a plum-size tumor from the 55-year-old Bayh, who had been suffering severe headaches for about two weeks, said Evan Bayh, a former Indiana governor and U.S. senator.

"We feel like our prayers were answered," he told The Associated Press in a phone interview. "We're physically and emotionally wrung out, but happy that it wasn't worse."

Bayh said his wife underwent 4 1/2 hours of surgery Monday morning and was heavily sedated in the intensive care unit several hours later.

"We're happy to have it behind us," he said. "She's going to be in the hospital for three or four days and hopefully on the road to recovery."

Republican Gov. Mike Pence and Democratic U.S. Sen. Joe Donnelly took to social media to say they hoped for a quick return to health.

Susan Bayh's headaches became so severe she stayed in bed for two or three days before undergoing a scan last week, her husband said.

"I got an emergency call from her doctor that there was a large mass on her brain and they were very fearful that it was malignant," Bayh said.

Further scans determined several hours later that the tumor was likely not cancerous but still needed to be removed soon because of its size and the risk of it causing seizures, he said.

The Bayhs have twin 19-year-old sons, Beau and Nick, who were born in 1995 while their father was governor. Bayh said both sons were with their parents at the hospital.

"That was better than any medication, having them hold her hand," he said.

Susan Bayh is an attorney who's been a member of several corporate boards. The Bayhs have lived in Washington since Evan Bayh was elected to the U.S. Senate in 1998. The Democrat didn't seek election to a third Senate term in 2010.

Pence's official Twitter account said he and first lady Karen Pence "are thankful for a good report following Susan Bayh's surgery and send our prayers for a swift recovery."

Donnelly said on Twitter that "on behalf of all Hoosiers, I wish Susan a speedy recovery and hope to hear soon that she has received a clean bill of health."